Reward Processing in Psychiatric Inpatients With Depression.

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Major depressive disorder (MDD) is commonly linked to reward-circuit dysfunction.
• Previous studies show reduced reward responses in MDD, but the link to symptom severity versus comorbidities is unclear.

Purpose of the Study:

• To investigate reward-processing differences in patients with severe depressive symptoms (DEPs) compared to psychiatric controls (PCs) and healthy controls.
• To determine if reward-processing dysfunction in MDD is associated with symptom severity or comorbid diagnoses.

Main Methods:

• Functional magnetic resonance imaging (fMRI) using a juice-delivery task.
• Comparison of DEPs (n=108) with PCs (n=108) and healthy controls (n=62).
• DEPs were matched to healthy controls demographically and to PCs for demographics and psychiatric diagnoses.

Main Results:

• DEPs exhibited significantly smaller responses to reward stimulus in the left putamen compared to PCs and healthy controls.
• Exploratory analysis revealed lower reward responses in DEPs within the bilateral dorsal striatum, middle frontal gyrus, left precentral gyrus, and middle cingulate cortex.
• Reduced reward responses in the left putamen were correlated with depressive symptom severity in both DEPs and PCs.

Conclusions:

• Individuals with severe depressive symptoms may have a diminished capacity to modulate behavior based on rewards.
• Reward-processing dysfunction, particularly in the left putamen, is associated with the severity of depressive symptoms in MDD.
• Findings highlight the impact of depression severity on neural reward pathways.